Evidence for excess vacancy defects in the Pd-Si system: positron annihilation, x-ray diffraction and Auger electron spectroscopy study

The transformation of Pd/Si to Pd2Si/Si is investigated using depth-resolved positron annihilation, x-ray diffraction and Auger electron spectroscopy studies. The observed defect-sensitive positron S-parameter value of 1.022-1.054 indicates the existence of divacancies across the silicide/silicon interface and Si substrate region. Our experimental observation of vacancy defects is consistent with the model proposed for excess vacancy generation across the interface consequent to Si diffusion.